What is a common adverse reaction of calcium supplements?

Calcium supplements can lead to hypercalcemia, which is an elevated level of calcium in the blood. This condition often results from taking excessive amounts of calcium, especially through supplements, as the body has a limited capability to excrete excess calcium. Hypercalcemia may present with various symptoms including fatigue, nausea, vomiting, constipation, and in more severe cases, confusion and arrhythmias. It's essential for healthcare providers to monitor calcium levels in patients who are on long-term calcium supplementation to prevent this adverse effect.

While other options may reflect potential effects associated with imbalances in electrolytes or nutrients, hypercalcemia distinctly aligns with the intake of calcium supplements, hence making it the most common adverse reaction to be aware of.